2^6 DIVISION II. — COURSE OF DEVELOPMENT OF FUNGI. 



are many gradations in the scale of arrestment and of perfection. Still it is more 

 correct in such cases to speak not of arrest of development, but of different adaptation, 

 or the metamorphosis of members, as we call foliage leaves, tendrils, and anthers in 

 their various adaptations metamorphosed leaves or phyllomes, but do not call foliage- 

 leaves rudimentary anthers, or anthers rudimentary foliage-leaves. At present we will 

 keep to the correct and customary usage and apply the term rudimentary to those 

 parts only which are arrested in respect to their development as members or 

 structures, and also as regards their capacity in every respect for discharging their 

 proper functions. 



There is still another phenomenon which is allied in many points to unusual 

 metamorphosis and rudimentary development of members and yet is distinct from it, 

 namely, the occurrence of organs which are well developed and capable of performing 

 their function, but which, as far as can be ascertained, are actually functionless. The 

 phenomenon is of course rare ; but the antheridia and archegonia of the apogamous 

 Ferns 1 afford an example of its actual appearance among the organs of reproduction, 

 which, from the facts recorded elsewhere, may be considered as beyond doubt. The 

 occurrence therefore of this phenomenon must not be forgotten when we are engaged 

 in deciding about doubtful formations. 



The doubtful formations which we have to consider here are first of all the 

 ' doubtful sporocarps ' of the Aspergilli (and Sterigmatocystis of Van Tieghem), 

 and secondly most spermatia and spermogonia. The Aspergilli show exactly 

 the course of development of Penicillium. The doubtful sporocarps (p. 206) 

 are bodies that look like sclerotia and resemble the perithecia of Penicillium, but 

 differ from these, according to some observers at least, in that they show no 

 development of asci. Brefeld's statements 2 to the contrary have been silently 

 withdrawn or ignored by himself s since the appearance of Wilhelm's profound treatise 

 on the subject. The question then naturally arises, what was the reason for the 

 negative results respecting the formation of asci which were all that were obtained 

 during so many years ? Brefeld answers the question by declaring these bodies to be 

 ' rudimentary primordia of perithecia.' This may be so with the bodies which 

 Brefeld found in Aspergillus flavus and which he describes as undifferentiated tuber- 

 like structures. But Wilhelm repeatedly obtained from A. flavus as well as from 

 the other species a large number of well-developed bodies of the nature of sclerotia 

 which in A. flavus had a black rind ; the development therefore goes in this 

 case also beyond the undifferentiated rudiment. 



These bodies in view of their structure can no more be called rudimentary 

 than the sclerotia of Penicillium. The difference in structure which seems actually 

 to be found in all cases, namely, that there are no distinct ascogenous hyphae 

 such as appear in the sclerotia of Penicillium, cannot be of any importance, for this 

 difference exists in like manner up to the commencing formation of asci between 

 other primordial sporocarps, the perithecia of Claviceps and Pleospora for instance, on 

 one side and those of Melanospora and others on the other. It may be allowed that 

 these objections would be merely a playing with words, if there were sufficient grounds 



See above, p. 122. 2 Bot. Ztg. 1876, p. 265. 



3 Schimmelpilze, IV, 134. 



